Models 375 (Including Series One), 375/1, 375/2 & 375/4 Section 5
Ludlum Measurements, Inc. Page 5-9 May 2017
SPECIFICATIONS
Power Required: 7.5 Vdc at 100 mA; minimum V
in
= 5.5 V and
maximum V
in
= 15 V (connected internally)
Terminating Resistor: 250 ohm
Model 375 4 to 20 mA Isolated Output Connections (3-pin Hirose
connector)
Pin 1 is black (negative).
Pin 2 is white (positive).
Internal Board Header Pinout
P1-1) Loop GND (Isolated)
P1-2) 4-20 current output (Isolated)
P2-1) +7.5 Vdc , RAWDC from main circuit board number 5396-160
(May range from +5.5 to 15 Vdc)
P2-2) GND
P2-3) RCDR voltage in or analog input (0-1.25 Vdc)
CALIBRATION
Apply 0 counts or RESET the Model 375.
Check for a voltage of 1.00 V ±5% across Rterm, typically a 250 ohm (V
= 0.004 X Rterm) terminating resistor. The resistor should be placed
between Pin 5 (the 4-20 mA output) and Pin 6 (Loop ground).
Note:
Loop ground is isolated from instrument ground.
Now apply a full-scale meter reading to the analog input, or move the
CAL dipswitch to the right. The voltage at full-scale must be set to 5.00 V
±0.1 V between the analog input and instrument ground.
Note:
Instrument ground is not the same as loop ground.
Adjust the SPAN trimmer, R5, until the voltage across the 250-ohm
terminating resistor is 5 V ±5% (V= .020 X Rtem).
To Next Page
Loading...
